This invention relates to sewage pump station construction and more particularly to improvements which prevent noxious sewer gases such as methane and hydrogen sulfide from entering the enclosure in which machinery is housed.
Sewage pumping stations of the type that are mounted on top of a concrete sewage wet wall ordinarily have numerous holes and openings in the bottom deck plate or floor of the machinery enclosure. Bolts and other fasteners, connecting rods, rotating shafts, and electrical components and wires commonly extend through such holes, and access to the underside of the station for repair or maintenance has been provided by a removable lid covering a manway opening in such a bottom deck plate. Attempts to hermetically seal such holes and openings with conventional means such as gaskets have failed because bolts loosen from vibration and flexure of the deck plate, shafts and bushings wear loose, and all such components are subject to deterioration from the moisture and corrosive gasses that are almost always present at the underside of the deck plate. Breaking of the hermetic seal in any of these ways results in sewer gases entering the machinery enclosure where they present health hazards to workers and an explosion risk because the pumps are electrically powered. Also, any omission of a part or any error in the way such components are installed or sealed usually permit entry of these gases.